1-(4′-Carboxyphenyl)-2-methyl-3-(piperidine-1-yl)-propan-1-one M3, erythro-1-(4′- carboxyphenyl)-2-methyl-3-(piperidine-1-yl)-propan-1-ol M4 and threo-1-(4′- carboxyphenyl)-2-methyl-3-(piperidine-1-yl)-propan-1-ol M5, metabolites of the muscle relaxant tolperisone were synthesized in racemic and optically active forms.